1. Field of the Invention
The present invention relates to a semi-conductor laser apparatus in which a light transmitting member for transmitting the output light generated by a semi-conductor laser element is bonded with a support member for said light transmitting member thereby hermetically to seal the interior of said support member.
2. Description of the Prior Art
In FIG. 1 there is shown a conventional semi-conductor laser apparatus in a partially broken schematic perspective view from which the lead wires to various terminals are omitted for the purpose of clarity, and in which there are represented a metallic base member 1, a cylindrical support member 2, an optical window 3 and a semi-conductor laser element 4 which is positioned in a sealed space defined by said support member 2, base member 1 and optical window 3.
Said optical window is usually composed of glass which is fused sealed to said support member 2 for achieving a necessary hermetic seal.
Such optical window sealed by a conventional glass fusion method has been obtained in the following manner. At first the support member 2 and the optical window 3 of predetermined sizes are set in a predetermined relationship, then subjected to a slow fusion in a furnace of a temperature determined by the species of the glass to be used for said optical window, said temperature being generally in a range of 400.degree. to 500.degree. C., and cooled in the furnace or in the air. However, though such glass fusion method provides satisfactory adhesion, the high temperature required for the treatment results in formation of distortion on the glass surfaces or of streaks and bubbles in the glass. Such optical window eventually enlarges the spot diameter of the laser beam when focused through a lens system, thus rendering impossible the use of such semi-conductor laser in the equipment requiring a high resolution.